The present invention relates to sheet fabrication centers and machines such as for example turret punch presses, and more particularly a sheet fabrication machine that utilizes a direction conversion mechanism for driving the tool of the machine.
The aforenoted ""576 application discloses a sheet fabrication machine that utilizes a contact mechanism, in the form of a roller for example, that is movable along the direction parallel to the plane of the worksheet, for making contact with the ram of the tool assembly for driving the tool in a direction that is essentially orthogonal to the direction in which the roller is driven. By thus converting a force that is movable in one direction for driving the tool in another direction, the machine as described in the ""576 application is able to perform a number of innovative techniques that could not be achieved, or achieved with great difficulties, by prior sheet fabrication machines.
As disclosed in the ""576 application, the mechanism for converting the drive movement along one direction into a driving force in another direction is provided by the interaction between a roller and a preconfigured mechanism such as for example a cam. Such mechanism works well so long as the work to be performed on a worksheet requires a particular force at a given speed. To change to a different force, for the machine as described in the ""576 application, either the roller or the cam of the force direction conversion mechanism has to be replaced. Needless to say, such replacement not only is time consuming but requires that the machine be shut down during the mechanism exchange process.
An improved force direction conversion mechanism is therefore needed for enhancing the operation of a sheet fabrication machine.
The improved sheet fabrication machine of the instant invention utilizes a plurality of cams working cooperatively with a contact mechanism such as for example a roller. In a first embodiment, the plurality of cams are fixedly mounted to a carriage plate that is positioned over the tool mechanism. The carriage plate is movable, by means of either hydraulic or servo drives, to position one of the cams to interpose between the roller and the tool. Once accurately positioned, by moving the roller in one direction such as for example the x axis, the cam, which has at least one surface that makes contact with the roller, would convert the force supplied by the roller in the x direction into another direction such as for example along the z axis, to thereby drive the tool along the z axis.
The tool, for the invention at hand, could also mean the die. Thus, two different carriage plates, one for the upper tool and one for the lower tool such as for example the die, could be provided to correspondingly drive both tools in a manner as described in the aforenoted ""576 application.
To move the carriage plate so as to position a particular cam over the tool, and more particularly the ram that drives the tool, a drive mechanism such as for example a servomotor or a hydraulic drive may be used. The positioning of the carriage plate may be done in an accurate fashion by means of a ball screw drive, whose accuracy may be monitored by the coupling of a sensor thereto.
The positioning of the carriage plate may be done in a linear fashion. Alternatively, a rotational movement of the carriage plate may be effected to align the appropriate cam between the drive roller and the ram of the machine. Such rotational movement is especially effective if there are even numbers of cams concentrically mounted onto the carriage plate.
In place of positioning a carriage plate with a plurality of cams mounted thereon between the drive roller and the ram, a second embodiment of the instant invention sheet fabrication machine has mounted to a carriage movable along a linear guide in a first direction a plurality of cams. These cams are mounted in line along the carriage so that, as the carriage is driven along the first direction, a particular cam would come into contact with a contact mechanism mounted over the ram, so that the ram is driven along an other direction to drive the tool. By controlling the movement of the carriage along the guide, the tool may be driven with different forces at different speeds via the different cams.
For the first embodiment whereby a plurality of cams are mounted to a carriage plate, insofar as only one of the cams is positioned between the drive mechanism and the ram at any one time, the idle cam can in fact be exchanged for another cam while the machine is in operation.
It is therefore an objective of the present invention to provide a sheet fabrication machine with a force direction conversion mechanism that allows the user to select from among a number of choices the desired cam with the appropriate speed and force for punching the tool.
It is another objective of the present invention to provide a user a choice of the force and speed with which he can operate the punch of the machine without having to first idle or stop the operation of the machine.
It is yet another objective of the present invention to provide a sheet fabrication machine that can fabricate a worksheet with different forces and speeds during the same operation.